In April this year Facebook - ahead of its IPO - moved to buy Instagram for $1bn. Since then, the dominant social network's shares have bombed and are now worth about half the price, tottering around $19 compared with Facebook's $38 float on Wall Street just three months ago.

What this means in practice is that the regulatory delay in probing Facebook's bid has ended up stinging Instagram, as sagely pointed out by the New York Times earlier this week.

Instagram, of course, made the mistake of accepting Facebook's terms not to pay $1bn in an all-cash handshake.

Instead, the photo filter app's makers stand to receive 300 million green dollars and around 23 million Facebook shares after the deal is sealed.

Unless Facebook shares suddenly rocket, Instagram - based on today's stock price - will lose about a quarter of the $1bn initially tabled by Mark Zuckerburg's company, which has gotta hurt.

But, if the closing price were to stand at $750m, then it still represents an awful lot of cash and shares for a phone app that paints a nappypoo glaze across digital photographs. ®